The present invention relates generally to railroad infrastructure, and more particularly to railroad switches in un-signaled (dark) territory.
The United States rail system is currently comprised of approximately 143,000 track miles, of which, approximately only 70,000 miles are currently signaled. Signal systems are generally comprised of wayside signals, power operated switches, vital track circuits, and “vital” field logic implemented in either relay-based systems, or solid state devices (note that the use of the term “vital” in this application is associated in the industry with known performance and reliability parameters, and does not mean “vital” in a patentability sense, or patent-interpretation sense, unless otherwise explicitly stated herein). The signal systems provide for the safe control and movement of railway vehicles through the operation of the signals and switches. This control is predominantly accomplished through the use of Centralized Traffic Control (CTC) systems where a dispatcher remotely controls the signals and switches. Signal systems, CTC systems, and their components, are well known and understood in the current art. Such systems are not applied universally due to the high costs of acquisition and maintenance.
The remaining 70,000 miles of track are considered to be “dark” territory. Movement of railway vehicles in dark territory is governed by verbal communication and authorization, issued by a dispatcher, thereby maintaining the safe separation and movement of the railway vehicles. These verbal communications can be automated, however, automated systems comprise multiple points of potential failure. It would therefore be advantageous to reduce the points of potential failure for a dark-territory automated railroad track circuit.